Methods and apparatuses for controlling operation of a vibrational output system and/or operation of an input sensor system

ABSTRACT

Embodiments described herein relate to methods and apparatuses for controlling an operation of a vibrational output system and/or an operation of an input sensor system, wherein the controller is for use in a device comprising the vibrational output system and the input sensor system. A controller comprises an input configured to receive an indication of activation or de-activation of an output of the vibrational output system; and an adjustment module configured to adjust the operation of the vibrational output system and/or the operation of the input sensor system based on the indication to reduce an interference expected to be caused by the output of the vibrational output system on the input sensory system.

TECHNICAL FIELD

The present disclosure describes methods and apparatuses for thereduction or prevention of interference (e.g. haptic crosstalk) expectedto be caused by the output of the vibrational output system on an inputsensory system. The input sensory system may comprise, for example, aforce sensing input system to provide virtual buttons, or other inputsensory system such as an accelerometer, gyroscope, or microphone.

RELATED APPLICATIONS

The present disclosure relates to U.S. patent application Ser. No.15/722,128 filed Oct. 2, 2017; U.S. patent application Ser. No.16/267,079 filed Feb. 4, 2019; U.S. patent application Ser. No.16/294,347 filed Mar. 6, 2019; and U.S. patent application Ser. No.16/422,543 filed May 24, 2019, all of which are incorporated byreference herein in their entireties.

BACKGROUND

Linear resonant actuators (LRAs) and other vibrational actuators (e.g.,rotational actuators, vibrating motors, etc.) are increasingly beingused in mobile devices (e.g., mobile phones, personal digitalassistants, video game controllers, etc.) or other systems to generatevibrational feedback for user interaction with such devices. Typically,a force/pressure sensor detects user interaction with the device (e.g.,a finger press on a virtual button of the device) and in responsethereto, the linear resonant actuator vibrates to provide feedback tothe user. For example, a linear resonant actuator may vibrate inresponse to force to mimic to the user the feel of a mechanical buttonclick.

One disadvantage of existing haptic systems is that existing approachesto processing of signals of a force sensor and generating of a hapticresponse thereto often have longer than desired latency, such that thehaptic response may be significantly delayed from the user's interactionwith the force sensor. Thus, in applications in which a haptic system isused for mechanical button replacement, capacitive sensor feedback, orother application, and the haptic response may not effectively mimic thefeel of a mechanical button click. Accordingly, systems and methods thatminimize latency between a user's interaction with a force sensor and ahaptic response to the interaction are desired.

In addition, to create appropriate and pleasant haptic feelings for auser, a signal driving a linear resonant actuator may need to becarefully designed and generated. In mechanical button replacementapplication, a desirable haptic response may be one in which thevibrational impulse generated by the linear resonant actuator should bestrong enough to give a user prominent notification as a response tohis/her finger pressing and/or releasing, and the vibrational impulseshould be short, fast, and clean from resonance tails to provide a usera “sharp” and “crisp” feeling. Optionally, different control algorithmsand stimulus may be applied to a linear resonant actuator, to alter theperformance to provide alternate tactile feedback—possibly denotingcertain user modes in the device—giving more “soft” and “resonant”tactile responses.

SUMMARY

According to some embodiments there is provided a controller forcontrolling an operation of a vibrational output system and/or anoperation of an input sensor system, wherein the controller is for usein a device comprising the vibrational output system and the inputsensor system. The controller comprises an input configured to receivean indication of activation or de-activation of an output of thevibrational output system; and an adjustment module configured to adjustthe operation of the vibrational output system and/or the operation ofthe input sensor system based on the indication to reduce aninterference expected to be caused by the output of the vibrationaloutput system on the input sensory system.

According to some embodiments there is provided a device. The devicecomprises an input sensor system; a vibrational output system; acontroller configured to control operation of the vibrational outputsystem and/or the input sensor system, wherein the controller comprises:an input configured to receive an indication indicating activation ordeactivation of an output of the vibrational output system; and anadjustment module configured to adjust operation of the vibrationaloutput system and/or operation of the input sensor system based on theindication to reduce an interference expected to be caused by the outputof the vibrational output system on the input sensory system.

According to some embodiments there is provided an integrated circuitfor use in a device comprising an input sensor system and a vibrationaloutput system. The integrated circuit comprising a controller configuredto control operation of the vibrational output system and/or the inputsensor system, wherein the controller comprises: an input configured toreceive an indication of whether an output of the vibrational outputsystem is active; and an adjustment module configured to adjustoperation of the vibrational output system and/or operation of the inputsensor system based on the indication.

According to some embodiments there is provided a method for use in adevice comprising a vibrational output system and an input sensor systemfor controlling operation of the vibrational output system and/or theinput sensor system. The method comprises receiving an indication ofwhether an output of the vibrational output system is active; andadjusting operation of the vibrational output system and/or operation ofthe input sensor system based on the indication to reduce aninterference expected to be caused by the output of the vibrationaloutput system on the input sensory system.

According to some embodiments there is provided a controller foroutputting an output signal to a vibrational output system for use in adevice comprising the vibrational output system and an input sensorsystem. The controller comprises an input for receiving an input signal;and a filter for filtering the input signal to provide the outputsignal; wherein the filter is configured to filter the input signalbased on an operating or carrier frequency associated with the inputsensor system. In some embodiments, the controller further comprises aninput configured to receive an indication of the operating or carrierfrequency of the input sensor system, and an adjustment moduleconfigured to dynamically adjust the filtering of the filter based onthe indication of the operating or carrier frequency of the input sensorsystem.

According to some embodiments there is provided a controller foroutputting an output signal to a vibrational output system for use in adevice comprising the vibrational output system and an input sensorsystem. The controller comprises a processing block configured to outputthe output signal, wherein the processing block is configured such thatinteger harmonic tones of the output signal fall outside a frequencyband associated with operation of the input sensor system. In someembodiments the processing block comprises an output pulse widthmodulation, PWM, amplifier. In some embodiments the controller furthercomprises an input configured to receive an indication of the frequencyband associated with operation of the input sensor system; and anadjustment module configured to dynamically adjust the operation of theprocessing block based on the received indication such that integerharmonic tones of the output signal fall outside the frequency bandassociated with operation of the input sensor system.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the embodiments of the present disclosure,and to show how it may be put into effect, reference will now be made,by way of example only, to the accompanying drawings, in which:

FIG. 1 illustrates a block diagram of selected components of an examplemobile device;

FIG. 2 illustrates a block diagram of selected components of an exampleintegrated haptic system;

FIG. 3 illustrates an example inductive sensing system;

FIG. 4 illustrates a virtual button implemented using an inductivesensing system such as the system illustrated in FIG. 3;

FIG. 5 illustrates a Human-Machine Interface (HMI) system comprising anintegrated haptic system;

FIG. 6 illustrates an example of an inductive sensing system;

FIG. 7 illustrates the band-of-interest BWc for an inductive sensingsub-system;

FIG. 8 illustrates a controller for controlling operation of avibrational output system and/or operation of an input sensor systemaccording to some embodiments;

FIG. 9 illustrates a controller in an HMI system according to someembodiments;

FIG. 10 illustrates an example of an adjustment module according to someembodiments; and

FIG. 11 illustrates a method for use in a device comprising avibrational output system and an input sensor system for controllingoperation of the vibrational output system and/or the input sensorsystem according to some embodiments.

DESCRIPTION

The description below sets forth example embodiments according to thisdisclosure. Further example embodiments and implementations will beapparent to those having ordinary skill in the art. Further, thosehaving ordinary skill in the art will recognize that various equivalenttechniques may be applied in lieu of, or in conjunction with, theembodiments discussed below, and all such equivalents should be deemedas being encompassed by the present disclosure.

The methods described herein can be implemented in a wide range ofdevices and systems, for example a mobile telephone, an audio player, avideo player, a mobile computing platform, a games device, a remotecontroller device, a toy, a machine, or a home automation controller ora domestic appliance. However, for ease of explanation of oneembodiment, an illustrative example will be described in FIG. 1, inwhich the implementation occurs in a mobile device 102.

FIG. 1 illustrates a block diagram of selected components of an examplemobile device 102, in accordance with embodiments of the presentdisclosure. As shown in FIG. 1, the mobile device 102 may comprise anenclosure 101, a controller 103, a memory 104, a input sensor system 105(which in this example comprises a force sensor), a microphone 106, avibrational output system 107 (which in this example comprises a linearresonant actuator (LRA)), a radio transmitter/receiver 108, a speaker110, and an integrated haptic system 112. It will be understood that anysuitable vibrational actuators arranged to provide a haptic vibrationeffect (e.g., rotational actuators such as ERMs, vibrating motors, etc.)may be used as an alternative to or in addition to the LRA 107.

Enclosure 101 may comprise any suitable housing, casing, or otherenclosure for housing the various components of mobile device 102.Enclosure 101 may be constructed from plastic, metal, and/or any othersuitable materials. In addition, enclosure 101 may be adapted (e.g.,sized and shaped) such that mobile device 102 is readily transported ona person of a user of mobile device 102. Accordingly, mobile device 102may include but is not limited to a smart phone, a tablet computingdevice, a handheld computing device, a personal digital assistant, anotebook computer, a video game controller, or any other device that maybe readily transported on a person of a user of mobile device 102. WhileFIG. 1 illustrates a mobile device, it will be understood that theillustrated systems may be utilized in other device types, e.g.user-interactable display technology, automotive computing systems, etc.

Controller 103 may be housed within enclosure 101 and may include anysystem, device, or apparatus configured to interpret and/or executeprogram instructions and/or process data, and may include, withoutlimitation, a microprocessor, microcontroller, digital signal processor(DSP), application specific integrated circuit (ASIC), or any otherdigital or analog circuitry configured to interpret and/or executeprogram instructions and/or process data. In some embodiments,controller 103 interprets and/or executes program instructions and/orprocesses data stored in memory 104 and/or other computer-readable mediaaccessible to controller 103.

Memory 104 may be housed within enclosure 101, may be communicativelycoupled to controller 103, and may include any system, device, orapparatus configured to retain program instructions and/or data for aperiod of time (e.g., computer-readable media). Memory 104 may includerandom access memory (RAM), electrically erasable programmable read-onlymemory (EEPROM), a Personal Computer Memory Card InternationalAssociation (PCMCIA) card, flash memory, magnetic storage, opto-magneticstorage, or any suitable selection and/or array of volatile ornon-volatile memory that retains data after power to mobile device 102is turned off.

Microphone 106 may be housed at least partially within enclosure 101,may be communicatively coupled to controller 103, and may comprise anysystem, device, or apparatus configured to convert sound incident atmicrophone 106 to an electrical signal that may be processed bycontroller 103, wherein such sound is converted to an electrical signalusing a diaphragm or membrane having an electrical capacitance thatvaries as based on sonic vibrations received at the diaphragm ormembrane. Microphone 106 may include an electrostatic microphone, acondenser microphone, an electret microphone, a microelectromechanicalsystems (MEMS) microphone, or any other suitable capacitive microphone.

Radio transmitter/receiver 108 may be housed within enclosure 101, maybe communicatively coupled to controller 103, and may include anysystem, device, or apparatus configured to, with the aid of an antenna,generate and transmit radio-frequency signals as well as receiveradio-frequency signals and convert the information carried by suchreceived signals into a form usable by controller 103. Radiotransmitter/receiver 108 may be configured to transmit and/or receivevarious types of radio-frequency signals, including without limitation,cellular communications (e.g., 2G, 3G, 4G, 5G, LTE, etc.), short-rangewireless communications (e.g., BLUETOOTH), commercial radio signals,television signals, satellite radio signals (e.g., GPS), WirelessFidelity, etc.

A speaker 110 may be housed at least partially within enclosure 101 ormay be external to enclosure 101, may be communicatively coupled tocontroller 103, and may comprise any system, device, or apparatusconfigured to produce sound in response to electrical audio signalinput. In some embodiments, a speaker may comprise a dynamicloudspeaker, which employs a lightweight diaphragm mechanically coupledto a rigid frame via a flexible suspension that constrains a voice coilto move axially through a cylindrical magnetic gap. When an electricalsignal is applied to the voice coil, a magnetic field is created by theelectric current in the voice coil, making it a variable electromagnet.The coil and the driver's magnetic system interact, generating amechanical force that causes the coil (and thus, the attached cone) tomove back and forth, thereby reproducing sound under the control of theapplied electrical signal coming from the amplifier.

The input sensor system 105 may be housed within, be located on or formpart of the enclosure 101 and may be communicatively coupled to thecontroller 103. In this example, the input sensor system 105 comprises aforce sensor system, and each force sensor of the force sensor system105 may include any suitable system, device, or apparatus for sensing aforce, a pressure, or a touch (e.g., an interaction with a human finger)and for generating an electrical or electronic signal in response tosuch force, pressure, or touch. In some embodiments, such electrical orelectronic signal may be a function of a magnitude of the force,pressure, or touch applied to the force sensor. In these and otherembodiments, such electronic or electrical signal may comprise ageneral-purpose input/output signal (GPIO) associated with an inputsignal to which haptic feedback is given.

Example force sensors may include or comprise:

-   -   capacitive displacement sensors,    -   inductive force sensors,    -   strain gauges,    -   piezoelectric force sensors,    -   force sensing resistors,    -   piezoresistive force sensors,    -   thin film force sensors, and    -   quantum tunneling composite-based force sensors.

In some arrangements, other types of sensor may be employed. Forpurposes of clarity and exposition in this disclosure, the term “force”as used herein may refer not only to force, but to physical quantitiesindicative of force or analogous to force, such as, but not limited to,pressure and touch.

In this example, vibrational output system 107 comprises a Linearresonant actuator 107 which may be housed within enclosure 101, and mayinclude any suitable system, device, or apparatus for producing anoscillating mechanical force across a single axis. For example, in someembodiments, linear resonant actuator 107 may rely on an alternatingcurrent voltage to drive a voice coil pressed against a moving massconnected to a spring. When the voice coil is driven at the resonantfrequency of the spring, linear resonant actuator 107 may vibrate with aperceptible force. Thus, linear resonant actuator 107 may be useful inhaptic applications within a specific frequency range. While, for thepurposes of clarity and exposition, this disclosure is described inrelation to the use of linear resonant actuator 107, it is understoodthat any other type or types of vibrational actuators (e.g., eccentricrotating mass actuators) may be used in lieu of or in addition to linearresonant actuator 107. In addition, it is also understood that actuatorsarranged to produce an oscillating mechanical force across multiple axesmay be used in lieu of or in addition to linear resonant actuator 107.As described elsewhere in this disclosure, a linear resonant actuator107, based on a signal received from integrated haptic system 112, mayrender haptic feedback to a user of mobile device 102 for at least oneof mechanical button replacement and capacitive sensor feedback.

Integrated haptic system 112 may be housed within enclosure 101, may becommunicatively coupled to input sensor system 105 and vibrationaloutput system 107, and may include any system, device, or apparatusconfigured to receive a signal from input sensor system 105 indicativeof a force applied to mobile device 102 (e.g., a force applied by ahuman finger to a virtual button of mobile device 102) and generate anelectronic signal for driving linear resonant actuator 107 in responseto the force applied to mobile device 102.

Although specific example components are depicted above as beingintegral to mobile device 102 (e.g., controller 103, memory 104, userinterface 105, microphone 106, radio transmitter/receiver 108,speakers(s) 110), a mobile device 102 in accordance with this disclosuremay comprise one or more components not specifically enumerated above.For example, although FIG. 1 depicts certain user interface components,mobile device 102 may include one or more other user interfacecomponents in addition to those depicted in the above figure, includingbut not limited to a keypad, a touch screen, and a display, thusallowing a user to interact with and/or otherwise manipulate mobiledevice 102 and its associated components.

In addition, it will be understood that the input sensor system 105 maycomprise additional or alternative input sensor devices or transducers,for example accelerometers, gyroscopes, cameras, or other sensordevices.

FIG. 2 illustrates a block diagram of selected components of an exampleintegrated haptic system 112A, in accordance with embodiments of thepresent disclosure. In some embodiments, integrated haptic system 112Amay be used to implement the integrated haptic system 112 of FIG. 1. Asshown in FIG. 2, integrated haptic system 112A may include a controller(which in this example comprises a digital signal processor (DSP)) 202,a memory 204, and an amplifier 206.

DSP 202 may include any system, device, or apparatus configured tointerpret and/or execute program instructions and/or process data. Insome embodiments, DSP 202 may interpret and/or execute programinstructions and/or process data stored in memory 204 and/or othercomputer-readable media accessible to DSP 202. The DSP 202 operates as acontroller for the integrated haptic system 112A.

Memory 204 may be communicatively coupled to DSP 202, and may includeany system, device, or apparatus configured to retain programinstructions and/or data for a period of time (e.g., computer-readablemedia). Memory 204 may include random access memory (RAM), electricallyerasable programmable read-only memory (EEPROM), a Personal ComputerMemory Card International Association (PCMCIA) card, flash memory,magnetic storage, opto-magnetic storage, or any suitable selectionand/or array of volatile or non-volatile memory that retains data afterpower to mobile device 102 is turned off.

Amplifier 206 may be electrically coupled to DSP 202 and may compriseany suitable electronic system, device, or apparatus configured toincrease the power of an input signal VIN (e.g., a time-varying voltageor current) to generate an output signal VOUT. For example, amplifier206 may use electric power from a power supply (not explicitly shown) toincrease the amplitude of a signal. Amplifier 206 may include anysuitable amplifier class, including without limitation, a Class-Damplifier.

In operation, memory 204 may store one or more haptic playbackrepresentations. A haptic playback representation may comprise awaveform. In some examples, a haptic playback representation maycomprise one or more parameters, for example, frequency amplitude andduration, allowing for the determination of a haptic waveform based onthe parameters. In some embodiments, each of the one or more hapticplayback representations may define a haptic response a(t) as a desiredacceleration of a linear resonant actuator (e.g., linear resonantactuator 107) as a function of time.

The controller or DSP 202 is configured to receive a force signal VSENSEfrom force sensor system 105 indicative of force applied to at least oneforce sensor of the force sensor system 105. Either in response toreceipt of force signal VSENSE indicating a sensed force orindependently of such receipt, DSP 202 may retrieve a haptic playbackrepresentation from memory 104 and may process the haptic playbackrepresentation to determine a processed haptic playback signal VIN. Inembodiments in which amplifier 206 is a Class D amplifier, processedhaptic playback signal VIN may comprise a pulse-width modulated signal.In response to receipt of force signal VSENSE indicating a sensed force,DSP 202 may cause processed haptic playback signal VIN to be output toamplifier 206, and amplifier 206 may amplify processed haptic playbacksignal VIN to generate a haptic output signal VOUT for driving linearresonant actuator 107.

In some embodiments, integrated haptic system 112A may be formed on asingle integrated circuit, thus enabling lower latency than existingapproaches to haptic feedback control. By providing integrated hapticsystem 112A as part of a single monolithic integrated circuit, latenciesbetween various interfaces and system components of integrated hapticsystem 112A may be reduced or eliminated.

For devices having input transducers, for example resistive or inductiveforce sensors, or other input sensor systems such as microphones,accelerometers, gyroscopes, optical sensors, etc., the system may beconfigured such that any effect or interference expected to be caused bythe vibrational output on the input sensor system is reduced. This maybe done by controlling the operation of the vibrational output,controlling the operation of the input sensor system, and/or controllingthe processing of signals produced by the input sensor system to reducethe effect of any vibrational-related crosstalk.

Inductive Sense in Human-Machine Interface (HMI) Systems

In an example embodiment, the input sensor system may comprise a systemconfigured to measure the variation in the inductance of a coil referredto as an inductive sensing system. The inductive sensing system may formpart of a Human-Machine Interface (HMI).

FIG. 3 illustrates an example inductive sensing system. The inductivesensing system comprises a metal plate 301 and inductor 302 located at acertain distance 303. When a current (I) passes through the inductor302, the magnetic field induces Eddy currents inside the metal plate301. When a force, F, is applied to the metal plate, the forces changesthe distance 303 from the metal plate 301 to the inductor 302, andchanges the coupling between the inductor 302 and metal plate 301. Inthis case, the coupling coefficient k, inductor L2 and lossy resistanceRL in the model of the inductive sensing system changes. The change indistance 303, in turn, modifies the effective impedance looking into theinductor (ZL).

In such an inductive sensing system, a force or mechanical movement inthe metal place will result in a change in inductance.

FIG. 4 illustrates a virtual button implemented using an inductivesensing system such as the system illustrated in FIG. 3.

When such inductive sensing systems are used as part of an HMI system,haptic feedback may be included in the HMI system to provide usertactile feedback based on the amount/duration of pressure applied.Examples of such a HMI interface may include, but are not limited tovirtual button systems, volume sliders, power/home buttons in electronicdevices.

FIG. 5 illustrates an HMI system 500 comprising an integrated hapticsystem 510. The integrated haptic system 112A of FIG. 2 may comprise theintegrated haptic system 510. The HMI system 500 comprises of three mainsub-systems: an RLC sensor 501, an inductive sensing analog front end(AFE) 502 with post-processing, and a haptic amplifier 503 that isconnected to the sensing sub-system. The haptic amplifier 503 providestactile feedback to the user through the haptic module 504, e.g. an LRAor similar. As described with reference to FIG. 2, controller 505 (whichmay comprise a DSP) may be configured to control operation of the hapticamplifier 503. In particular, the DSP 505 may be configured to receive aforce signal V_(SENSE) from IS AFE 502 indicative of force applied tothe inductive sensor 501. Either in response to receipt of force signalV_(SENSE) indicating a sensed force or independently of such receipt,the DSP 505 may retrieve a haptic playback representation from memory506 and may process the haptic playback representation to determine aprocessed haptic playback signal VIN.

In systems such as those mentioned above, it may be advantageous toensure that the vibrational output system (for example a hapticamplifier and module, or a surface audio system) does not interfere oraffect the functionality of the inductive sensing system. For example,when actively vibrating, energy may couple from the vibrational outputsystem back to the inductive sensing system or the sensor, therebyaffecting the detection accuracy of the inductive sensing system or thesensor. It will be understood that the general structure of theabove-described smart haptic amplifier with an integrated inductiveforce sensing front end may apply for a system with an integrated inputsensor system (e.g. resistive force sensing) front end.

It will also be appreciated that a vibrational output system may have asimilar interfering effect on other types of input sensor system, forexample camera systems, optical systems, microphones etc.

Inductive Sensing

FIG. 6 illustrates an example of an inductive sensing system 600 thatmeasures phase shift (called phase detector hereafter), which isproportional to the coil inductance. The IS AFE 502 illustrated in FIG.5 may comprise the inductive sensing system 600 illustrated in FIG. 6.

The inductive sensing system 600 may be coupled to a sensor (Sensor)603, wherein the sensor 603 comprises a resistive-inductive-capacitive(R-L-C) circuit. (This may be equivalent to the inductive sensor 501illustrated in FIG. 5).

-   -   The inductance in the R-L-C circuit may comprise a coil and a        metal plate,    -   The voltage across the sensor 603 may be generated based on the        R-L-C circuit response to the current driven into the sensor        603.    -   Note—the resistive component R of the sensor 603 is not        illustrated in FIG. 6 but will be understood as being present as        an intentional or parasitic circuit component.

In this example, the inductive sensing system 600 comprises thefollowing:

(1) A digitally controlled oscillator (DCO) 601 wherein:

-   -   The DCO 601 outputs a clock at a carrier frequency (Fc),        referred to as the 0 degree output; and    -   The DCO 601 outputs a second square wave clock that is        notionally 90 degrees shifted relative to the primary output,        referred to as the 90 degree output.        (2) A drive circuit (Driver) 602 wherein:    -   The output of the DCO 601 is coupled to the input of the driver        602;    -   The drive circuit 602 drives a pseudo-sinusoidal current at the        frequency and phase alignment of the 0 degree clock input; and    -   The drive circuit 602 drives a fixed amplitude current.    -   It will be understood that the driver 602 may drive a constant        current at a drive frequency of 0 Hz.        (3) A I-Q receive path that receives the voltage across the        sensor comprising    -   A low noise input amplifier (Amplifier) 604;    -   An I Path coupled to the output of the amplifier comprising:        -   An analog multiplier 605 with inputs coupled to:            -   the DCO 601 output that is phase aligned to the current                transmitted by the driver circuit, and            -   the output of the amplifier 604;        -   A low-pass filter 606 coupled to the output of the analog            multiplier 605; and        -   An ADC 607 coupled to the output of the low pass filter to            digitize the I path voltage signal.    -   A Q Path coupled to the output of the amplifier 604 comprising:        -   An analog multiplier 608 with inputs coupled to:            -   the DCO 601 output that is phase offset by 90 degrees to                the signal transmitted by the driver circuit, and            -   the output of the amplifier 604;        -   A low-pass filter 609 coupled to the output of the analog            multiplier 608; and        -   An ADC 610 coupled to the output of the low pass filter 609            to digitize the Q path voltage signal.            (4) A processing block (POST PROCESSING) 611 that generates            amplitude and phase information from the I-Q paths wherein:    -   The I Path ADC 607 output is coupled as an input into the        processing block; and    -   The Q Path ADC 610 output is coupled as an input into the        processing block.

The DSP 505 may then comprise a button press detection block 612 thatobserves the phase information to determine if the shift in phaserecorded by the I-Q detection path is interpreted as a button press.

In this example inductive sensing system 600, to perform one scan of theR-L-C sensor 603 the following may be performed:

-   -   The DCO 601 and drive current 602 are activated.    -   After the low pass filter(s) 609, 606 have settled, the ADC(s)        610, 607 are activated and one or multiple ADC samples are        captured at a capture frequency, preferably at approximately 500        kHz.        -   The duration over which the ADC samples are captured is            referred to as the conversion time.        -   Each ADC sample contains a certain amount of noise due to            analog and digital factors including, but not limited to:            -   Circuit thermal noise            -   Circuit flicker noise            -   Digital quantization noise    -   One or multiple ADC samples are filtered to attenuate noise.    -   Processing converts the I and Q signals into phase and amplitude        information.

It will be appreciated that, whilst the filtering in FIG. 6 isillustrated as occurring on the ADCs 610, 607 outputs, the filtering mayoccur at multiple different places in the processing path. In addition,it will be understood that a voltage-controlled oscillator (VCO) may beused instead of a DCO 601 for the above-described system.

The power in the inductive sensing system 600 may vary based on a numberof factors, for example:

-   -   Scan rate: if more scans are performed within a certain measure        of time, the power will increase compared to less scans        performed.    -   Conversion time: longer conversion times require the circuits to        be active for a longer time, increasing power consumption.

Returning to FIG. 5, the output of the inductive sensing systemV_(SENSE) may be used by the DSP 505 to trigger the haptic amplifier503, which may playback any one of the stored haptic representations inthe memory 506 to the haptic module 504 based on the type of tactilefeedback needed. The haptic amplifier 503 may be implemented as aClass-D system and as such, may have significant out of band content(e.g. outside of the 0-20 Khz band that is used to transmit the signal)going up to several tens of megahertz.

One example of a haptic amplifier output is a Pulse Width Modulated(PWM) stream that, in addition to the signal power being located in 0-20Khz band, has harmonics and out of band noise up to 50 Mhz or above.

In such a system, the haptic amplifier output may have noise or tonalcontent in the same operating frequency range as the inductive sensoritself (i.e. within the range of the carrier frequency Fc). This may addnoise to the inductive sense phase calculations, affecting accuracy,functionality or both.

To address this, the HMI system 500 may be configured as follows.

The sensor 501 described in the system may be comprised of aresistive-inductive-capacitive (R-L-C) circuit, whose inductivecomponent is comprised of a metal coil, which is nominally an antenna,and as such is capable of detecting electromagnetic fields external tothe system.

In examples in which the IS AFE 502 comprises the inductive sensingsystem 600 as described in FIG. 6, the inductive sensing sub-system 600comprises the I-Q Receive Path, which is comprised of analog mixers andlow-pass filters. Once the Analog-Digital Conversion is complete, theremay also be digital filtering applied to the signals. There is afrequency band-of-interest for the input signal that the inductivesensing sub-system is trying to detect, and thus the I-Q Receive Pathmay be designed to intrinsically reject signals outside this band. Theamount of rejection varies with the frequency of the signal applied andhow close it is to the band-of-interest (a band around a carrierfrequency Fc). External interference that lies within this band maydegrade the signal-to-noise ratio and lead to reduced accuracy of theinductive sensing sub-system.

In a system co-habited by both an input sensor system (such as inductivesensing system 600) and a vibrational output system (such as a hapticamplifier and a haptic module), a portion of the noise or distortionproduced by the vibrational output system may fall directly within theband-of-interest (BWc) of the input sensor system (or in the closeneighborhood of BWc), and may degrade the phase or amplitude measurementaccuracy.

FIG. 7 illustrates the band-of-interest BWc for an inductive sensingsub-system.

It will be appreciated that the output energy of the vibrational outputsystem may couple to the input sensor system causeinaccuracies—especially when the output energy is close to the carrierfrequency Fc of the input sensor system. Coupling mechanisms mayinclude, but are not limited to electrical coupling, mechanical couplingor vibrational coupling. IT will also be appreciated that the outputenergy of the vibrational output system may result in some thermaleffects. For example, if the input sensor system is dependent ontemperature, or the output of the input sensor system varies in some waywith temperature, then the vibrational output system may couple with theinput sensor system by heating up the input sensor system whilst thevibrational output system is active.

One example of electrical coupling may occur when a trace or parasiticcapacitance exists between for example a haptic amplifier output of thevibrational output system and a sensor input (or output) of the inputsensor system. The out-of-band for example, PWM content output by thevibrational output system may couple onto the sensor signal path as anexternal interferer. Other coupling mechanisms may include power-supplycoupling, inductive or electromagnetic coupling, or IC substratecoupling.

FIG. 8 illustrates a controller 800 for controlling operation of avibrational output system and/or operation of an input sensor systemaccording to some embodiments. The controller is for use in a devicecomprising the vibrational output system and the input sensor system.For example, the device may comprise the device 101 illustrated in FIG.1, and the integrated haptic system 112 illustrated in FIG. 1 (or 112Aillustrated in FIG. 2) may comprise a controller 800 as illustrated inFIG. 8. In particular, the DSP 202 of FIG. 2, or DSP 505 of FIG. 5 maycomprise a controller 800 as described with reference to FIG. 8.

The controller 800 comprises an input 801 configured to receive anindication of activation or de-activation of an output of thevibrational output system. For example, the indication may comprise thesignal V_(SENSE) from a force sensor 105 as illustrated in FIG. 2. Thesignal V_(SENSE) may indicate activation of an output of the vibrationaloutput system when the signal V_(SENSE) indicates that a force is sensedat the force sensor 105 as the controller may be configured, asdescribed above, to output a vibrational output signal to thevibrational output system in response to the signal V_(SENSE) indicatingthat a force has been sensed at the force sensor.

In some embodiments, the indication may comprise the haptic playbacksignal V_(IN). In these examples, a delay may be applied to the hapticplayback signal V_(IN) before outputting the signal to the haptic modulein order to account for any delay in processing provided by thecontroller 800. The haptic playback signal V_(IN) may indicateactivation of an output of the vibrational output system, for example,when the haptic playback signal is non-zero or has an amplitude above apredetermined threshold.

The controller 800 further comprises an adjustment module 802 configuredto adjust the operation of the vibrational output system and/or theoperation of the input sensor system based on the indication to reducean interference expected to be caused by the output of the vibrationaloutput system on the input sensory system. For example, the controller800 may be configured to output a control signal CTRL to one or both thevibrational output system and the input sensor system.

In some examples, the indication may be processed by a processing block803 before input into the adjustment module 802. For example, where theindication comprises the signal V_(SENSE) the controller may comprise abutton press detection block 803, for example, the button pressdetection block 612 as illustrated in FIG. 6. The button press detectionblock 612 may then output an indication to the adjustment moduleindicating whether or not the signal V_(SENSE) is indicative of a buttonpress. However, in some examples, the button press detection block mayform part of the input sensor system, and the controller 800 may receivethe indication of whether or not the signal V_(SENSE) is indicative of abutton press.

It will be appreciated that the processing block 803 perform differentprocessing depending on the nature of the input sensor system. Forexample, if the input sensor system comprises a camera sensor system,the processing block 803 may be configured to determine whether or notthe camera is being used.

Given an input sensor system and a vibrational output system, one ormore of the following approaches may be used to ensure optimalefficiency and co-design with zero or minimal loss of sensitivity,accuracy and functionality. It will be understood that the describedapproaches may be implemented by a controller 800 provided as part ofthe input sensor system and/or as part of the integrated haptic systemor smart haptic amplifier as described above.

For example, the input sensor system 902 may comprise an inductivesensing system 600 as illustrated in FIG. 6. The inductive sensingsystem 600 may have several programmable/variable parameters that may beadjusted by the adjustment module 802 in response to the indication. Forexample, the filtering applied by the inductive sensing, for example,the time and bandwidth used in either the analog filtering or digitalfiltering (post-ADC) may be variable. The higher the time (and lower theBW), the narrower the BWc produced. The drive amplitude of the inductivesensing system 600 may also be adjusted. For example, the amplitude ofthe signal driven to the sensor 603 may be variable. By varying thedrive signal to the sensor 603, the adjustment module 802 may vary theSNR by varying the “signal” portion of SNR. These examples (and others)will be described in more detail below with reference to FIG. 9.

FIG. 9 illustrates the controller 800 in an HMI system 900. The HMIsystem 900 may form part of a device. The HMI system 900 comprises avibrational output system 901, an input sensor system 902 and controller800.

The vibrational output system 901 may also comprise any suitablevibrational output system for example a haptic output system or asurface audio output system.

In this example, the vibrational output system 901 comprises a hapticoutput system and the input sensor system 902 comprises a force sensorsystem.

The controller 800 is configured to receive the output of the inductivesensing analog front end 502. The detection block 803 may then determinewhether the output of the inductive sensing AFE 502 is representative ofa button press. It will be appreciated that in embodiments in which theinput sensor system comprises another type of sensor (for example acamera), the detection block 803 may be configured to detect when theinput sensor system is outputting a signal during which it is desirableto output a vibrational output to the user of the device.

The adjustment module 802 may then be configured to output a controlsignal CTRL to one or both of the vibrational output system 901 and theinput sensor system 902 based on the output of the detection block 803.

For example, the adjustment module 802 may be configured to increase adrive amplitude or a power level of the input sensor system 902responsive to the indication indicating activation of the output of thevibrational output system 901. Since the output of the inductive sensingAFE 502 may be used to determine if the haptic amplifier needs to beactivated, the drive amplitude (or power level) to the input sensor 501may be temporarily increased for the duration that the vibrationaloutput system is active. In this way, the total signal to noise ratio(SNR) of the signal output by the input sensor 501 may still meet aminimum threshold. In other words, whilst the noise or interferencecaused by the vibrational output system may remain the same as if therewere no adjustment made by the adjustment module 802, the amplitude ofthe sensor signal is increased to compensate.

For example, referring to FIG. 6, the adjustment module 802 may beconfigured to control the drive circuit 602 so that the drive amplitudeto the sensor is increased responsive to the indication indicatingactivation of the output of the vibrational output system 901.

In some examples, the adjustment module 802 is configured to adjust abandwidth or conversion time associated with operation of the inputsensor system responsive to the indication indicating activation of theoutput of the vibrational output system.

For example, the bandwidth associated with operation of the input sensorsystem may comprise a filtering bandwidth applied to an output signal ofthe input sensor system, and wherein the adjustment module is configuredto reduce the filtering bandwidth responsive to the indicationindicating activation of the output of the vibrational output system.For example, the adjustment module 802 may be configured to adjust thefiltering bandwidth applied by the filters 609 and/or 606 in theinductive sensing system 502.

For example, the filtering bandwidth (BW) or conversion time in theinductive sensing AFE 502 may be adapted when the haptic amplifier isactivated. For example, the filtering BW may be adjusted by theadjustment module 802 to be much narrower around the carrier frequencyF_(c). By narrowing the filtering bandwidth, a higher proportion of theinterfering vibrational output signal may be filtered out of the signalV_(SENSE) thereby reducing the interference expected to be caused by theoutput of the vibrational output system on the input sensory system.

The adjustment of the filtering bandwidth or conversion time may befurther optimized by calibration. The calibration maybe performed eitherat a stage of initial manufacture or assembly of a device, or inreal-time. To perform the calibration, a zero signal may be driven intothe input sensor 501 while the vibrational output system 901 isactivated, and the output of the inductive sensing AFE 502 (e.g. thephase and/or amplitude) may be measured. In this way, only theinterference caused by the vibrational output signal is being measuredfrom the output of the inductive sensing AFE 502.

To calibrate the system, the filtering bandwidth of the inductivesensing AFE 502 and/or the conversion time of the inductive sensing AFE502 may be changed (for example iteratively) until the output of theinductive sensing AFE 502 falls below a pre-determined noise threshold.The filtering BW and/or conversion time settings that cause the outputof the inductive sensing AFE 502 to fall below the pre-determined noisethreshold may be then stored in on-device or local memory.

The adjustment module 802 may then, (for example, during normaloperation of the device), be configured to obtain a bandwidth orconversion time setting from a memory; and apply the bandwidth orconversion time setting to the input sensor system 902 whilst theindication indicates activation of the output of the vibrational outputsystem. In other words, during normal operation of the system (e.g.where the signal driven into the input sensor 501 may be non-zero) whenthe vibrational output system is activated (or to be activated), thestored filtering BW and/or conversion time settings may be retrievedfrom the memory and applied to the inductive sensing AFE 502 such thatthe output of the inductive sensing AFE 502 is effectively set as noise.

Once the indication indicates that the vibrational output system 901 isno longer active, the inductive sensing AFE 502 may be returned to theoriginal filtering and/or conversion time settings for regular sensoroperation.

In some examples, the adjustment module may be configured to applydigital post-compensation. In this example, the system may becalibrated. The calibration maybe performed either at the stage ofinitial manufacture or assembly, or in real-time. To perform thecalibration, a zero signal may be driven into the input sensor 501,while the vibrational output system 901 is activated and the output ofthe inductive sensing AFE 502 (e.g. the phase and/or amplitude) may bemeasured.

For example, as a particular output signal is output through thevibrational output system 901, the controller 800 may measure the outputof the inductive sensing AFE 502. A compensation waveform may then bedetermined for the particular output signal, wherein the compensationwaveform is the inverse of the output of the inductive sensing AFE 502during output of the output signal through the vibrational output system901. Compensation signals may be determined for a number ofpredetermined output signals (e.g. haptic playback signals) expected tobe output through the vibrational output system during normal operationof the device. Each compensation signal may be stored associated withthe respective associated output signal.

The adjustment module 802 may then be configured to: responsive to theindication indicating activation of the output of the vibrational outputsystem, obtain a compensation signal from a memory comprising one ormore stored compensation signals, wherein the compensation signal isassociated with an output signal for output by the vibrational outputsystem; and apply the compensation signal to a sensor signal (e.g.V_(SENSE)) output by the input sensor system whilst the output signal isoutput by the vibrational output system. For example, the adjustmentmodule 802 may be configured to add the compensation signal to theoutput of the inductive sensing AFE 502. By applying the compensationsignal to the sensor signal output by the inductive sensing AFE 502during output of the associated output signal, the expected interferenceof the output signal on the input sensor system 902 may be cancelledout. In this example, the compensation waveform may be applied to thesensor signal before the controller 800 processes the output of theinductive sensing AFE 502 to determine whether or not, for example, abutton press has occurred at the input sensor system 902.

When the indication indicates that the vibrational output system 901 isno longer active, the adjustment module 802 may be configured to nolonger apply the compensation signal to the sensor signal.

In some examples, the operating frequency of the input sensor system 902may be adjusted when the vibrational output system 901 is activated. Forexample, responsive to the indication indicating activation of theoutput of the vibrational output system, the adjustment module 802 maybe configured to select an operating frequency (for example, the carrierfrequency F_(c)) of the input sensor system based on an output signalbeing output by the vibrational output system.

Considering an example in which the vibrational output system 901comprises a haptic output system. If a harmonic tone of the hapticamplifier 503 is falling at or close to the operating frequency orcarrier frequency Fc of the input sensor system 902 such that it cannotbe filtered effectively by the inductive sensing AFE 502, The carrierfrequency (or operating frequency) Fc may be adjusted such that theharmonic tone may now be filtered. As the carrier frequency Fc may begenerally of the order of tens of MHz, changing Fc in the order of 100Khz does not materially change the sensitivity of the input sensorsystem 902, but may allow for filtering of the interference caused bythe harmonic tone as the harmonic tone may be forced out of thefiltering bandwidth applied by the inductive sensing AFE 502. Therefore,the adjustment module 802 may be configured to select the operatingfrequency of the input sensor system 902 such that the output signaloutput by the vibrational output system 901, or harmonic tones producedduring output of the output signal, do not lie within the filteringbandwidth of the input sensor system 902.

In some examples, a similar effect may be implemented using a keep-outzone provided with either factory or real-time calibration. For example,a zero signal may be driven into the input sensor system 902 and thevibrational output system 901 may be activated. The output of the inputsensor system 902 may then be measured during activation of thevibrational output system 901. In this way, only the interference causedby the activation of the vibrational output system 901 is beingmeasured. During measurement of the interference, the operatingfrequency (Fc) of the input sensor system 902 may be swept through arange of frequencies, and instances in which the IS AFE 502 output(phase and/or amplitude) falls above a pre-determined noise and/oraccuracy threshold are recorded. The frequency values associated withthese instances may then be stored and keep-out zones may be determinedthat comprise these frequency values. In this example, when thevibrational output system 901 is activated (or to be activated), thecarrier frequency Fc may be selected by the adjustment module 802 suchthat it does not fall in any of the keep-out zones. For example, theadjustment module 802 may be configured to responsive to the informationindicating activation of the output of the vibrational output system,select an operating frequency (e.g. carrier frequency F_(c)) of theinput sensor system such that the operating frequency does not liewithin a predefined keep-out zone.

Once the vibrational output system 901 is no longer activated, theoriginal settings can be resumed with no keep-out zones applied to theoperating frequency of the input sensor system 902.

In some examples, the adjustment module is configured to blank out theoutput signal of the input sensor system 902, for example, by settingthe output of the input sensor system 902 to zero, or otherwise causethe HMI system 900 to ignore the output of the input sensor system 902when the vibrational output system 901 is activated. For example, theadjustment module 802 may be configured to blank out an output signal ofthe input sensor system responsive to the indication indicatingactivation of the output of the vibrational output system. For example,the adjustment module may be configured to either power down the IS AFE502 or put the IS AFE 502 in standby, or the adjustment module may beconfigured to cause the controller 800 to simply ignore the data duringactivation of the vibrational output system 901.

For example, the adjustment module 802 may be configured to blank outthe output signal by one or more of: placing the input sensor system 902in a low power mode, putting the input sensor system 902 in an inactivemode, or ignoring the output signal of the input sensor system 902whilst the indication indicates activation of the output of thevibrational output system.

In some examples, the adjustment module 802 is configured to, responsiveto the indication indicating activation of the output of vibrationaloutput system 901, adjust the operation of the input sensor system 902such that the input sensor system 902 performs sensing only during oneor more time intervals during which an output signal being output to thevibrational output system has a vibrational amplitude below apredetermined threshold amplitude. For example, the output signal to beoutput to the vibrational output system 901 may be designed such thatthere are small time intervals (or quiet periods) in the vibratingpattern of the tactile feedback in which the amplitude of the outputsignal is below a predetermined threshold. In other words, during thesetime intervals any interference caused by the vibrational output systemon the input sensor system will be reduced due to the lower amplitude ofthe output signal. The input sensing system 902 may therefore performsensing during these time intervals when no or reduced interferenceassociated with the vibrational output system 901 is present. Thisembodiment may also ensure that no input data is lost (for example, nobutton press is missed at the input sensing system 902) as may be thecase in prolonged blanking intervals. In some examples, the adjustmentmodule 802 may be configured to adjust the operation of the input sensorsystem 902 by causing the controller 800 (or the button press detectionblock 803) to ignore the sensing signal V_(SENSE) outside of the timeintervals. Alternatively, the input sensing system 902 may bedeactivated by the adjustment module 802 during the time intervals.

In some examples, the adjustment module 802 is configured to, responsiveto the indication indicating activation of the output of vibrationaloutput system, trigger a desensitization window to apply to an output ofthe input sensor system. For example, when the vibrational output system901 is activated, for example where an output signal causing vibrationis output by the vibrational output system, the adjustment module 802may be configured to trigger a desensitisation window such that theoutput of the input sensor system 902 is desensitised in order tocompensate for the possible interference caused by the activation of thevibrational output system 901. The adjustment module 802 may beconfigured to trigger the desensitization window by adjusting operationof the input sensor system 902 for example, by adjusting a thresholdused by the input system 902 to detect an event so as to reduce thesensitivity of the input sensor system 902 to such events. In thisexample therefore the input sensor system 902 may be considered tocomprise the button press detection block 803. The adjustment module 800may then be configured to increase a threshold employed by the buttonpress detection block 803 to determine if a force indicated by theoutput of the IS AFE 502 is indicative of a button press. By increasingthis threshold, the adjustment module reduces the sensitivity of thebutton press detection block 803 to button press events.

In some examples, the adjustment module may be configured to trigger thedesensitization window by applying a negative gain to the output of asensor 501, or to the output of the input sensor system 902. This may beconsidered analogous to increasing the threshold at which the buttonpress detection block 803 will detect a button press event as byreducing the gain of the signal.

By effectively reducing the sensitivity of the input sensor system 902during the desensitization window, the adjustment module 802 maymitigate the impact of the activated vibrational output system 901 onthe input sensor system 902, or on any other systems relying on theoutput of the input sensor system 902. In some examples thedesensitization window may have a variable duration, which for examplecould be based on the duration of the vibration output signal and/or thepossibility of post-vibration-output “ringing”. In addition, a factor byadjustment module reduces the gain of the output of the input sensorsystem 902 or increases the threshold applied by the button pressdetection block 803 may be configured based on the amplitude of theoutput of the vibrational output system 901. As a further aspect, itwill be understood that the desensitization window may be split, forexample, the factor may vary during the duration of the desensitizationwindow.

It will be understood that some of the above-described functions of theadjustment module 802 may not be suitable for use with all types ofinput sensor system 902. For example, if the adjustment module isconfigured to blank out the output signal of the input sensor system,this may result in noticeable drop-outs or distortions if the inputsensor system comprises a microphone sensor system (e.g. during a voicecall), or the input sensory system comprises a gyroscope oraccelerometer sensor system (e.g. when motion of the device is beingused as an input to e.g. a gaming application). In examples such asthese (or with suitable input sensor system), the adjustment module 802may be configured as illustrated in FIG. 10.

FIG. 10 illustrates an example of an adjustment module 802 according tosome embodiments.

In this embodiment, the adjustment module 802 may be configured topredict the output effect of the vibrational output system 901 on theinput sensor system 902, and to determine the nature of any filteringthat may be performed to mitigate the effect of the vibrational outputsignal on the input sensor system 902.

In particular, it may be possible to model the vibrational output system901, the mechanical surroundings of the device, and the input sensorsystem 902. For example, it may be possible to regard the collectiveparts listed above as linear systems which may be modelled by anadaptive filter.

In this embodiment therefore, the adjustment module 802 comprises anadaptive filter 1001.

In FIG. 10, the transfer function h(n) represents the real transferfunction of the unknown system comprising the vibrational output system901, the mechanical surroundings of the device, and input sensor system902. For example, h(n) may represent the coupling effect between thevibrational output system and the device frame, input sensor system (andany other mechanical factors) on the vibrational output system.

The signal x(n) comprises the vibrational output signal. The signal y(n)then represents the vibrational output signal following coupling withthe input sensor system and any other mechanical factors of the device.

The signal v(n) represents the desired input sensor signal received atthe input sensor system, in other words the signal that would bereceived at the controller if the transfer function h(n) had no effecton the input sensor system. The signal d(n) then represents the signalactually output by the input sensor system that is affected by thevibrational output system and other mechanical effects of the deviceaccording to h(n). The signal d(n) may be received by the adaptivefilter 1001.

The model h{circumflex over ( )}(n) of the adaptive filter 1001 (whichmay be a model in the electrical domain) replicates the actual transferfunction h(n). The model h{circumflex over ( )}(n) may then becontinuously adapted to track changes in the actual system. Theadaptation of the model h{circumflex over ( )}(n) may be performed whenthere is no input sensor signal v(n) and/or the adaption rate may be atdifferent rate to the signal v(n) (for example, if v(n) is a fast signalh{circumflex over ( )}(n) may adapt slowly). The signal y{circumflexover ( )}(n) may therefore be representative of the signal y(n) suchthat when the model h{circumflex over ( )}(n) matches the actualtransfer function h(n) the signal e(n) is equivalent to the input sensorsignal v(n).

The adaptive filter may comprise a linear filter, such as a FiniteImpulse Response (FIR) or an Infinite Impulse Response (IIR) filter,which may be updated using appropriate adaptive filtering methods suchas recursive Least Mean Squares (LMS), Kalman filters, etc.

In some examples, the output e(n) may be limited when the interferenceis too high or the filter h{circumflex over ( )}(n) fails to track thereal transfer function h(n). This may be referred to as a non-linearcanceller.

In some examples, the input sensor system and/or vibrational outputsystem may be preconfigured for operation in conjunction with eachother.

For example, a controller (for example controller 800) may be providedfor outputting an output signal to the vibrational output system for usein a device comprising the vibrational output system and an input sensorsystem. The controller may comprise an input for receiving an inputsignal; and a filter for filtering the input signal to provide theoutput signal; wherein the filter is configured to filter the inputsignal based on an operating or carrier frequency associated with theinput sensor system. In other words, the controller may be preconfiguredwith the operating of carrier frequency of the input sensor system suchthat the output signal output by the vibrational output system isfiltered by the input sensor system and therefore the interferencecaused by the vibrational output system may be reduced or avoided.

In some examples, the filter may comprise one or more filter poles (ornotches) such that attenuation is provided in a narrow band based onwhere the pole is located in the frequency domain. In some examples, theone or more filter poles or notches may be programmable. For example,the controller 800 may comprise an input configured to receive anindication of the operating or carrier frequency of the input sensorsystem, and the adjustment module 802 may be configured to dynamicallyadjust the filtering of the filter based on the indication of theoperating or carrier frequency of the input sensor system. In this way,if, for operational reasons, the carrier frequency Fc (or operatingfrequency) of the input sensor system is changed dynamically or uponreset, then the notch or pole may also be changed appropriately.

One example of implementing the filter may be to implement a FiniteInfinite Response (FIR) filter in one of the stages of the vibrationaloutput system. With proper placement, the notch (or pole) may contributeto attenuating the output signal of the vibrational output system aswell as any noise or harmonics of the output signal that fall in thesame frequency band as the input sensor system operating frequency.

In some examples, a controller (for example controller 800) may beprovided for outputting an output signal to a vibrational output systemfor use in a device comprising the vibrational output system and aninput sensor system. The controller may comprise a processing blockconfigured to output the output signal, wherein the processing block isconfigured such that integer harmonic tones of the output signal falloutside a frequency band associated with operation of the input sensorsystem. The processing block may comprise an output pulse widthmodulation, PWM, amplifier. For example, once the set of sensoroperating frequencies (Fc) is known, the fundamental PWM frequency ofthe haptic amplifier may be selected such that none of its integerharmonic tones fall within a predetermined band of Fc.

In some examples, the controller 800 may comprise an input configured toreceive an indication of the frequency band associated with operation ofthe input sensor system. The adjustment module 802 may then beconfigured to dynamically adjust the operation of the processing blockbased on the received indication such that integer harmonic tones of theoutput signal fall outside the frequency band associated with operationof the input sensor system. In some examples the controller may beconfigured to vary the edge rate of the PWM waveform to change itsharmonic content such that the harmonic tones of the output signal falloutside the frequency band associated with operation of the input sensorsystem.

FIG. 11 illustrates a method for use in a device comprising avibrational output system and an input sensor system for controllingoperation of the vibrational output system and/or the input sensorsystem. The method may be performed by a controller (for examplecontroller 800 as illustrated in FIGS. 8, 9 and 10). In some examples,the method may be implemented by a DSP, such as DSP 202 illustrated inFIG. 2 or DSP 505 of FIG. 5.

In step 1101 the method comprises receiving an indication of whether anoutput of the vibrational output system is active. For example, theindication may comprise the signal V_(SENSE) from a force sensor 105 asillustrated in FIG. 2. The signal V_(SENSE) may indicate activation ofthe output of the vibrational output system when the signal V_(SENSE)indicates that a force is sensed at the force sensor 105 as thecontroller may be configured, as described above, to output avibrational output signal to the vibrational output system in responseto the signal V_(SENSE) indicating that a force has been sensed at theforce sensor.

In some embodiments, the indication may comprise the haptic playbacksignal V_(IN). In these examples, a delay may be applied to the hapticplayback signal V_(IN) before outputting the signal to the haptic modulein order to account for any delay in processing provided by thecontroller 800. The haptic playback signal V_(IN) may indicateactivation of an output of the vibrational output system, for example,when the haptic playback signal is non-zero or has an amplitude above apredetermined threshold.

In step 1102, the method comprises adjusting operation of thevibrational output system and/or operation of the input sensor systembased on the indication to reduce an interference expected to be causedby the output of the vibrational output system on the input sensorysystem. For example, as described with reference to FIGS. 8 and 9, thestep 1102 may comprise any of the functional operations described asbeing performed by the adjustment module 802. It will however beappreciated that the functional operations may be performed by differentfunctional blocks.

It will be understood that the above approaches described for aninductive sensing system may also be used for other sensing systems asappropriate. For example, a smart haptic amplifier having a resistiveforce sensing front end may be configured to implement appropriatesensor compensation, blanking windows and/or adaptive haptic output asdescribed above. Similar approaches may be used for any other suitablesensor system in a device, e.g. for the output of an accelerometer,gyroscope, etc., sensor compensation, blanking windows and/or adaptivehaptic output as described above may also be used.

In a further aspect, the input sensor system may comprise a camera orother type of optical sensor, wherein the controller 800 is arranged tocontrol the camera or optical sensor itself, and/or is arranged toperform compensation on the output of the camera or optical sensor, toreduce the effect of haptic or other vibrational output signals on thesensor system. The controller 800 may perform image stabilization basedat least in part on the vibrational output.

It will be understood that the above-described system and methods mayalso be used for the reduction or elimination of crosstalk from surfaceaudio-based systems, where at least one actuator is used to driveoscillation or vibration of a surface of a device, e.g. a screen or caseof a mobile phone, to produce acoustic output. As such systems utilizemechanical vibrations of a portion of the device to produce deviceaudio, the vibrations may interact with existing input sensors ortransducers similar to the haptic crosstalk as described above. In suchcases, it will be understood that a surface audio amplifier may be usedin place of the haptic amplifier as described above.

It will be understood that the above-described methods may beimplemented in a dedicated control module, for example a processingmodule or DSP as shown in the above figures. The control module may beprovided as an integral part of the sensor system or may be provided aspart of a centralized controller such as a central processing unit (CPU)or applications processor (AP). It will be understood that the controlmodule may be provided with a suitable memory storage module for storingmeasured and calculated data for use in the described processes.

The skilled person will recognise that some aspects of theabove-described apparatus and methods may be embodied as processorcontrol code, for example on a non-volatile carrier medium such as adisk, CD- or DVD-ROM, programmed memory such as read only memory(Firmware), or on a data carrier such as an optical or electrical signalcarrier. For many applications embodiments of the invention will beimplemented on a DSP (Digital Signal Processor), ASIC (ApplicationSpecific Integrated Circuit) or FPGA (Field Programmable Gate Array).Thus the code may comprise conventional program code or microcode or,for example code for setting up or controlling an ASIC or FPGA. The codemay also comprise code for dynamically configuring re-configurableapparatus such as re-programmable logic gate arrays. Similarly the codemay comprise code for a hardware description language such as Verilog™or VHDL (Very high speed integrated circuit Hardware DescriptionLanguage). As the skilled person will appreciate, the code may bedistributed between a plurality of coupled components in communicationwith one another. Where appropriate, the embodiments may also beimplemented using code running on a field-(re)programmable analoguearray or similar device in order to configure analogue hardware.

Note that as used herein the term “module” or the term “block” shall beused to refer to a functional unit or block which may be implemented atleast partly by dedicated hardware components such as custom definedcircuitry and/or at least partly be implemented by one or more softwareprocessors or appropriate code running on a suitable general purposeprocessor or the like. A module may itself comprise other modules orfunctional units. A module may be provided by multiple components orsub-modules which need not be co-located and could be provided ondifferent integrated circuits and/or running on different processors.

Embodiments may be implemented in a host device, especially a portableand/or battery powered host device such as a mobile computing device forexample a laptop or tablet computer, a games console, a remote controldevice, a home automation controller or a domestic appliance including adomestic temperature or lighting control system, a toy, a machine suchas a robot, an audio player, a video player, or a mobile telephone forexample a smartphone. There is further provided a host deviceincorporating the above-described system.

It should be understood—especially by those having ordinary skill in theart with the benefit of this disclosure—that the various operationsdescribed herein, particularly in connection with the figures, may beimplemented by other circuitry or other hardware components. The orderin which each operation of a given method is performed may be changed,and various elements of the systems illustrated herein may be added,reordered, combined, omitted, modified, etc. It is intended that thisdisclosure embrace all such modifications and changes and, accordingly,the above description should be regarded in an illustrative rather thana restrictive sense.

Similarly, although this disclosure makes reference to specificembodiments, certain modifications and changes can be made to thoseembodiments without departing from the scope and coverage of thisdisclosure. Moreover, any benefits, advantages, or solutions to problemsthat are described herein with regard to specific embodiments are notintended to be construed as a critical, required, or essential featureor element.

Further embodiments likewise, with the benefit of this disclosure, willbe apparent to those having ordinary skill in the art, and suchembodiments should be deemed as being encompassed herein.

It should be noted that the above-mentioned embodiments illustraterather than limit the invention, and that those skilled in the art willbe able to design many alternative embodiments without departing fromthe scope of the appended claims. The word “comprising” does not excludethe presence of elements or steps other than those listed in a claim,“a” or “an” does not exclude a plurality, and a single feature or otherunit may fulfil the functions of several units recited in the claims.Any reference numerals or labels in the claims shall not be construed soas to limit their scope.

Aspects of the system may be defined by the following numberedstatements:

1. A device comprising:

-   -   an input sensor system;    -   a vibrational output system driven to provide vibrational        output;    -   a controller arranged to monitor the vibrational output system        and to adjust the operation of the vibrational output system        and/or the operation of the input sensor system to minimize the        effect of the vibrational output on the input sensor system.        2. Preferably, the vibrational output system comprises a haptic        output system arranged to provide a haptic vibrational output.        Additionally or alternatively, the vibrational output system        comprises a surface audio output system.        3. Preferably, the input sensor system comprises a force sensing        system.        4. Preferably, the force sensing system comprises at least one        force sensor selected from one or more of the following:    -   capacitive displacement sensors,    -   inductive force sensors,    -   strain gauges,    -   piezoelectric force sensors,    -   force sensing resistors,    -   piezoresistive force sensors,    -   thin film force sensors, and    -   quantum tunneling composite-based force sensors.        5. Additionally or alternatively, the input sensor system        comprises at least one of the following: an accelerometer, a        gyroscope, a microphone transducer, a camera, an optical sensor,        an ultrasonic sensor.        6. In one aspect, the controller adjusts the vibrational output        system such that the transfer function of the vibrational output        system comprises a notch or pole approximately at an operating        frequency of the input sensor system.        7. Preferably, the controller is configured to dynamically        adjust the vibrational output system such that the presence of a        notch or pole in the transfer function of the vibrational output        system is updated if the characteristics of the vibrational        output system and/or of the input sensor system change.        8. In an additional or alternative aspect, the controller is        configured to adjust an operating point of the input sensor        system based on an output of the vibrational output system.        9. Preferably, the controller is configured to increase a power        level or a drive amplitude of the input sensor system, to        increase the signal to noise ratio of the input sensor system.        10. In an additional or alternative aspect, the controller is        configured to adjust a bandwidth of operation of the input        sensor system based on an output of the vibrational output        system.        11. Preferably, the controller is arranged to adjust a filter        bandwidth of the input sensor system, preferably to reduce the        filter bandwidth to filter out interfering signals from the        vibrational output system.        12. Additionally or alternatively, the controller is configured        to adjust a conversion time of the input sensor system based on        an output of the vibrational output system.        13. In a further aspect, the device comprises:    -   a memory storage arranged to store a plurality of sensor system        profiles defining system characteristics such as a filter        bandwidth, a conversion time, a power level or a drive        amplitude;    -   wherein the controller is configured to select a sensor system        profile to adjust the operation of the input sensor system based        on the vibrational output system.        14. Preferably, the plurality of sensor system profiles define        different configurations of the input sensor system selected to        minimize the effect of the vibrational output on the input        sensor system.        15. In an additional or alternative aspect,    -   the vibrational output system comprises a haptic module        configured to drive a haptic actuator with a haptic waveform,    -   wherein the controller is provided with a plurality of digital        compensation waveforms based on an inverted version of the        effect of an individual haptic waveform on the input sensor        system, and    -   wherein the controller is configured to apply an individual        digital compensation waveform to the output of the input sensor        system in parallel with a haptic actuator being driven by a        corresponding haptic waveform.        16. In an additional or alternative aspect, the controller is        configured to adjust an operating frequency of at least a        portion of the input sensor system, to minimize the effect of        the vibrational output on the input sensor system.        17. Preferably, the device comprises:    -   a memory storage arranged to store a plurality of defined        keep-out zones defining frequency bands prone to interference        from a vibrational output of the vibrational output system,    -   wherein, responsive to a vibrational output of the vibrational        output system, the controller is arranged to adjust an operating        frequency of the input sensor system to not lie within a defined        keep-out zone.        18. In an additional or alternative aspect, the controller is        configured to adjust the operation of the vibrational output        system such that tones produced by a vibrational output of the        vibrational output system do not fall within a predetermined        frequency band of the input sensor system.        19. Preferably, the vibrational output system comprises an        output PWM amplifier, wherein the amplifier is controlled such        that none of the integer harmonic tones of the PWM amplifier        fall within a predetermined frequency band of the input sensor        system.        20. In an additional or alternative aspect, the controller is        configured to blank out the output of the input sensor system        while the vibrational output system is providing vibrational        output.        21. Preferably, the controller is configured to place the input        sensor system in a low power or inactive mode while the        vibrational output system is providing vibrational output.        22. In an additional or alternative aspect, the controller is        configured to control the output of the vibrational output        system such that the vibrational output is provided with        intervals of reduced vibrational amplitude, and wherein the        input sensor system is controller to sample input data during        such intervals of reduced vibrational amplitude.        23. In an additional or alternative aspect, the controller is        configured to apply a desensitization window to the input sensor        system, such that operational thresholds associated with the are        increased and/or a negative gain is applied to sensor signals of        the input sensor system, to reduce the impact of a vibrational        output on the input sensor system or on any systems using an        output of the input sensor system.        24. Preferably, the controller is configured to adjust a        duration and/or a desensitization factor of the desensitization        window.        25. In an additional or alternative aspect, the controller is        configured to implement an adaptive filter to model the effect        of a vibrational output has on the input sensor system, and to        derive an error signal used to compensate the output of the        input sensor signal.        26. In an additional or alternative aspect, the input sensor        signal comprises a camera or optical sensor, wherein the        controller is configured to perform image stabilization on the        output of the camera or optical sensor based at least in part on        the vibrational output.        27. In an alternative arrangement, there is provided an        integrated haptic system comprising:    -   an input sensor module arranged to receive an input from at        least one sensor, preferably a force sensing module arranged to        receive an input from at least one force sensor;    -   a haptic driver module arranged to output a haptic driver signal        to at least one haptic actuator; and    -   a control module arranged to control the haptic driver module        such that the haptic driver signal is based at least in part on        the input received from the at least one sensor,    -   wherein the control module is further arranged to monitor the        haptic driver module and to adjust the operation of the haptic        driver module and/or the operation of the input sensor module to        minimize the effect of a haptic vibrational output on the input        sensor module.        28. There is also provided a host device comprising at least one        system or device as described in any of the above numbered        statements.        29. A control method for a sensor system comprising the steps        of:    -   (a) monitoring a haptic vibrational output from a haptic module;    -   (b) controlling the operation of the haptic module and/or the        operation of an input sensor system to minimize the effect of        the haptic vibrational output on the input sensor system.

The invention claimed is:
 1. A controller for controlling an operation of a vibrational output system and/or an operation of an input sensor system, wherein the controller is for use in a device comprising the vibrational output system and the input sensor system, the controller comprising: an input configured to receive an indication of activation or de-activation of an output of the vibrational output system; and an adjustment module configured to adjust the operation of the vibrational output system and/or the operation of the input sensor system based on the indication to reduce an interference expected to be caused by the output of the vibrational output system on the input sensory system; wherein the adjustment module is configured to increase a drive amplitude or a power level of the input sensor system responsive to the indication indicating activation of the output of the vibrational output system.
 2. The controller of claim 1 wherein the drive amplitude or the power level of the input sensor system is increased such that a signal to noise ratio of the input sensor system meets a minimum threshold.
 3. The controller of claim 1 wherein the adjustment module is configured to adjust a bandwidth or conversion time associated with operation of the input sensor system responsive to the indication indicating activation of the output of the vibrational output system.
 4. The controller of claim 3 wherein the bandwidth associated with operation of the input sensor system comprises a filtering bandwidth applied to an output signal of the input sensor system, and wherein the adjustment module is configured to reduce the filtering bandwidth responsive to the indication indicating activation of the output of the vibrational output system.
 5. The controller of claim 3 wherein the adjustment module is configured to: obtain a bandwidth or conversion time setting from a memory; and apply the bandwidth or conversion time setting to the input sensor system whilst the indication indicating activation of the output of the vibrational output system.
 6. The controller of claim 1 wherein, the adjustment module is configured to: responsive to the indication indicating activation of the output of the vibrational output system, obtain a compensation signal from a memory comprising one or more stored compensation signals, wherein the compensation signal is associated with an output signal for output by the vibrational output system; and apply the compensation signal to a sensor signal output by the input sensor system whilst the output signal is output by the vibrational output system.
 7. The controller of claim 1 wherein the adjustment module is configured to: responsive to the indication indicating activation of the output of the vibrational output system, select an operating frequency of the input sensor system based on an output signal being output by the vibrational output system.
 8. The controller of claim 1 wherein the adjustment module is configured to: responsive to the indication indicating activation of the output of the vibrational output system, select an operating frequency of the input sensor system such that the operating frequency does not lie within a predefined keep-out zone.
 9. The controller of claim 1 wherein the adjustment module is configured to blank out an output signal of the input sensor system responsive to the indication indicating activation of the output of the vibrational output system.
 10. The controller of claim 9 wherein the adjustment module is configured to blank out the output signal by one or more of: placing the input sensor system in a low power mode, putting the input sensor system in an inactive mode, or ignoring the output signal of the input sensor system whilst the indication indicates activation of the output of the vibrational output system.
 11. The controller of claim 1 wherein the adjustment module is configured to, responsive to the indication indicating activation of the output of vibrational output system, adjust the operation of the input sensor system such that the input sensor system performs sensing only during one or more time intervals during which an output signal being output to the vibrational output system has a vibrational amplitude below a predetermined threshold amplitude.
 12. The controller of claim 1 wherein the adjustment module is configured to, responsive to the indication indicating activation of the output of vibrational output system, trigger a desensitization window to apply to an output of the input sensor system.
 13. The controller of claim 12 wherein the adjustment module is configured to trigger the desensitization window by one or more of: adjusting a threshold used by the input sensor system to detect an event to reduce the sensitivity of the input sensor system to events; and applying a negative gain to an output of a sensor in the input sensor system.
 14. The controller of claim 1 wherein the adjustment module comprises: an adaptive filter configured to: model an effect of an output signal of the vibrational output signal on an output signal of the input sensor system; and output an error signal based on the model, wherein the error signal is used to compensate the output signal of the input sensor system.
 15. A device comprising: an input sensor system; a vibrational output system; a controller configured to control operation of the vibrational output system and/or the input sensor system, wherein the controller comprises: an input configured to receive an indication indicating activation or deactivation of an output of the vibrational output system; and an adjustment module configured to adjust operation of the vibrational output system and/or operation of the input sensor system based on the indication to reduce an interference expected to be caused by the output of the vibrational output system on the input sensory system; wherein the adjustment module is configured to increase a drive amplitude or a power level of the input sensor system responsive to the indication indicating activation of the output of the vibrational output system.
 16. The device of claim 15 wherein the vibrational output system comprises a haptic output system configured to provide a haptic output.
 17. The device of claim 15 wherein vibrational output system comprises a surface audio output system.
 18. The device of claim 15 wherein the input sensor system comprises a force sensing system.
 19. The device of claim 18 wherein the force sensing system comprises at least one force sensor selected from one or more of: a capacitive displacement sensor; an inductive force sensor; a strain gauge; a piezoelectric force sensor; a force resisting sensor; a piezoresistive force sensor; a thin film force sensor; and a quantum tunnelling composite-based force sensor.
 20. The device of claim 15 wherein the input sensor system comprises at least one sensor selected from: an accelerometer; a gyroscope; a microphone transducer; a camera; an optical sensor; and an ultrasonic sensor.
 21. An integrated circuit for use in a device comprising an input sensor system and a vibrational output system, the integrated circuit comprising a controller configured to control operation of the vibrational output system and/or the input sensor system, wherein the controller comprises: an input configured to receive an indication of whether an output of the vibrational output system is active; and an adjustment module configured to adjust operation of the vibrational output system and/or operation of the input sensor system based on the indication; wherein the adjustment module is configured to increase a drive amplitude or a power level of the input sensor system responsive to the indication indicating activation of the output of the vibrational output system.
 22. A method for use in a device comprising a vibrational output system and an input sensor system for controlling operation of the vibrational output system and/or the input sensor system, the method comprising: receiving an indication of whether an output of the vibrational output system is active; and adjusting operation of the vibrational output system and/or operation of the input sensor system based on the indication to reduce an interference expected to be caused by the output of the vibrational output system on the input sensor system; wherein an adjustment module is configured to increase a drive amplitude or a power level of the input sensor system responsive to the indication indicating activation of the output of the vibrational output system. 